Effects of Light Treatment on Sleep, Cognition, Mood, and Behavior in Alzheimer’s Disease: A Systematic Review

Abstract

Background: Bright light treatment is a therapeutic intervention mainly used to treat sleep and circadian disturbances in Alzheimer’s disease (AD) patients. Recently, a handful of studies also focused on the effect on cognition and behavior. Conflicting findings are reported in the literature, and no definite conclusions have been drawn about its specific therapeutic effect. Summary: The aim of this review is to provide a critical evaluation of available evidence in this field, highlighting the specific characteristics of effective bright light treatment. Eligible studies were required to assess at least one of the following outcome measures: sleep, cognition, mood, and/or behavior (e.g., depression, agitation). A total of 32 articles were included in this systematic review and identified as research intervention studies about light treatment in AD. The quality of the papers was evaluated based on the US Preventive Service Task Force guidelines. Key Messages: Overall, the current literature suggests that the effects of light treatment in AD patients are mixed and may be influenced by several factors, but with a general trend toward a positive effect. Bright light seems to be a promising intervention treatment without significant adverse effects; therefore, further well-designed randomized controlled trials are needed taking into account the highlighted recommendations.

24-h Activity Rhythms and Health in Older Adults

“…Studies specifically intervening on circadian rhythms that take into account the 24-h activity rhythm remain scarce. A number of studies have reported reduced circadian disruption after bright light therapy in patients with dementia [80], Parkinson's disease [81], depression [82], cardiovascular disease [83], and cancer [84]. However, it is largely unknown to what extent intervening on circadian factors and, subsequently 24-h activity rhythms, improves relevant clinical outcomes such as disease progression or mortality.…”

Blue-wavelength Light Therapy for Post-traumatic Brain Injury Sleepiness, Sleep Disturbance, Depression, Fatigue: A Systematic Review and Network Meta-analysis

“…Its e cacy for depression and fatigue has also been reported in other medical and psychiatric conditions. For example, a recent review suggested that bright light therapy was effective for seasonal and non-seasonal depression and depression in dementia [39]. In addition, another systematic review also found that bright light therapy combined with psychosocial therapies was ranked the best in reducing cancer-related fatigue [40].…”

Exposing people with dementia to biodynamic light: The impact of biodynamic lighting on neuropsychiatric symptoms

“…The positive effect of light is also found in previous research. A recent systematic review of Mitolo et al (2018) on the effects of light treatment describe some studies that show some effect of bright light therapy on the reduction of agitation in people with dementia (Burns et al, 2009;Lovell et al, 1995;Mishima et al, 1994). Figueiro et al have shown the positive effect of light exposure in several studies (2014, 2015 & 2016).…”